This invention relates to an apparatus for automatically removing the skins from fruit. The invention has been devised particularly for processing Chinese gooseberries (Actinidia Chinensis).
A Chinese gooseberry is a fruit having a slightly elongated shape and is symmetrical about its longitudinal axis or core. The fruit tends to be almost cylindrical in shape, though the ends are somewhat rounded. The size of the fruit varies, depending to some extent upon its quality, but a typical Chinese gooseberry might have a length of approximately 4 - 5 cm and a diameter mid-way along its length of approximately 3 - 4 cm. The flesh of the fruit is delicate and tends to bruise easily and is covered with a delicate and thin skin from which projects a fibrous mat of fine bristles or hairs, which are about 1 - 2 mm in length. Usually the high quality fruit is sold in the as picked state to the public, this following a grading operation and perhaps an operation in which the fibrous hairs are removed. The lower quality or second grade fruit is processed for canning, though at present much is wasted because of the inefficiency of present hand processing methods whereby large quantities of fruit cannot be handled economically. In the past, because of the delicate nature of both the fruit itself, which makes it susceptible to bruising, and its thin skin, it has not been possible to machine process Chinese gooseberries and obtain a satisfactory product suitable for canning. For example, the present method of processing Chinese gooseberries involves mainly manual operations. The graded fruit usually has the fibrous hairs removed by friction, which may be achieved by passing the fruit through a system of roller brushes for example. With the fibrous hairs largely removed, the fruit then has its skin removed, perhaps after lye softening, by operators using hand held tools. This operation tends to be very time consuming as the fruit must be handled carefully and to achieve a reasonable rate of production, a large number of operators must be employed, this giving rise to high production costs and hence an expensive end product.
Often in preparing the fruit for canning, the fruit is sliced (usually transverse to its length). As the fruit which is being processed is usually still in its green stage, the core may tend to be rather hard which detracts from the quality of the end product. Where this is the case, the core of the Chinese gooseberry is removed before the slicing operation. In riper Chinese gooseberries the core is softer and this is not a problem.
In the past, numerous machines have been developed for the purpose of processing various fruits, this term including vegetables. However, these machines are not satisfactory for processing Chinese gooseberries. In some machines which use a lye bath and a washing operation to remove the skins from fruit, the fruit is handled in bulk at some stage in the operation, or several fruits are handled together which in the case of Chinese gooseberries would lead to bruising of the fruit. Other machines which have been devised to handle fruits separately throughout the skin removal operation, use spikes or similar projections to retain the fruit in a desired position, this commonly being used to ensure that the fruit is correctly aligned for a de-coring operation. Such spikes, if used with Chinese gooseberries, would also tend to bruise the fruit. Furthermore, a manual operation is usually required to place the fruit on the spikes.
Other machines have cups or similar receptacles in which individual fruits are located and conveyed through the processing apparatus. Individual fruits held in such receptacles tend to be retained in a substantially fixed position relative to the receptacle and there tends to be a large contact area between the fruit and the receptacle. This is a disadvantage where Chinese gooseberries are concerned because in spite of the usual operation to remove the fibrous hairs from the skin, a number of the hairs may still cling to the skin and act to retain bubbles of air in contact with the skin of the fruit when this is passing through the lye bath. When air remains in contact with the skin during this stage, the skin is not softened and loosened by the lye solution and later on in the process during the washing stage, the skin cannot be easily removed from the fruit. Such receptacles are not always entirely satisfactory for use even with fruits other than Chinese gooseberries where there is a large contact area between the fruit and the receptacle as this tends to reduce the effectiveness of the lye solution in loosening or softening the skin of the fruit where it is in contact with the receptacle.
Reference may be made to U.S. Pat. Nos. 3024822, 3096800, 3351112, 3352338 which illustrate the above comments and display the above mentioned disadvantages.